Electrical resistor construction



DSC, Q E950 J, y, ERNy 2,533,876

ELECTRICAL RESISTOR CONSTRUCTIN Filed July l5, 1948 Patented Dec. 12, 1950 UNITED STATES PATENT OFFICE 9 Claims.

This invention is directed to novel resistors, particularly of the type adapted for use in a Wide variety of electrical devices, electricalapparatus,

, electrical circuits and appliances. It is more primarily directed to novel structural features which provide a more suitable adaptation'of the elementary, unnished structure to the process of mechanically winding convolutions of a resistance wire thereon.

It is an important object of my invention to provide resistors which have an elongated, rounded or cylindrical body, which is composed of a non-conductive material, on the ends of which are terminal end units having a length which is equivalent to the diameter of the core,v

It is a further object of my invention to provide resistors in which a novel end unit is mounted on the ends of the resistor core and retained thereon due to the cooperation of the structure o said end unit and said core.

A further object of my invention is the provision of a means for precluding the slipping off of the resistance wire from the core of said resistor by employing terminal end members of unique design.

It is a further object of my invention to provide a resistor in which there is a core body composed of suitable non-conductive material with terminal end members mounted therein, in which the terminal end members provide the means for anchoring the ends of a resistance wire which is Wound around said core body.

A further object of my invention is to provide a core body which may be laid in an'end to end relation with other core bodies, separated only by the terminal end members mounted on the ends thereof, so that production line method of producing resistors is facilitated thereby.

It is a further object of my invention to provide a resistor having a uniform length of effective resistance Wire wound upon the core body thereof; and precluding the unwinding of the resistance Wire Wound upon the core body by providing metal end caps in which the terminal end members are mounted.

A further object of my invention is to provide a novel resistor which includes a core body; a uniform length of resistance Wire Wound thereon; terminal end members mounted on the ends of said core body, and which provide temporary anchoring means for the ends of the resistance Wire; metal end caps which are mounted on the terminal end members and secured thereto by means of a fusible metal of predetermined size.

It is a further object of, my invention to provide a novel resistor having the herein recited structures and in one form thereof which is provided `with a metal end cap having an integral, peripheral flange thereon which provides an abutment for a glass or other non-conductive sleeve placed 1 over the core of said resistor, and the resistance "wire Wound thereon. 1

It is a further object of my invention to provide a resistor which includes terminal end caps mounted on the ends thereof, and in each of which cap a terminal circuit Wire hasbeen securely mounted, said circuit wires being retained by a fusible metal. It is a further object of my invention to provide, in'a resistor, metal end caps mounted on the ends thereof which has an inwardly projecting flange so as to create a reservoir between said inwardly projecting flange and thewall of said metal end cap so that a pigtail Wire may be anchored in said cap by using a pellet of a fusible metal.

It is a further object of my invention to provide a method for making resistors in which the unexposed ends of circuit wires are each mounted lin a terminal end cap having an inwardly projecting annular flange, by means of a fusible metal, which in its fused state will not ow out of the cap through the opening defined by said annular flange.

Other and further important objects of my invention will be apparent from the following descriptions and appended claims.

' Referring `to the drawings:

Fig. 1 is a partial elevational view of one mechanism to which my core and terminal end assembly is adaptable for Winding of resistance wire thereon.

Fig. 2 is a sectional vieW of the core after winding of the resistance Wire thereon with one end cap mounted on the core taken substantially on the line 2`2 of Fig. 5.

Fig. 3 is a view of the terminal end member before being shaped for use.

Fig. 4 is an oblique detail view showing my end member ready for insertion into the core.

Fig.` 5 is an end view of the core with an end member inserted.

Fig. 6V is a'detail central longitudinal sectional View of one end of my resistor taken substantially on the line 6 6 of Fig. 8, after mounting the end members and caps thereon.

Fig. 7 is a detail eccentric longitudinal sectional view of one end of one modied form of my resistor, taken substantially on the line l-T of Fig. 5, after mounting the end caps thereon` Fig.- 3 ,LS .all @nd view of the core` Referring to the drawings, numeral I represents a core, body or member which is preferable cylindrical or rounded. The core Il) is preferably composed of a suitable non-conductive material such as porcelain. As illustrated in Fig. 8 in cross section, preferably an equilateral triangular passage is positioned substantially centrally with respect to the longitudinal axis of said core In so that a triangular hole II is present at each end of said core. It is to be understood that I the holes II need not be triangular, but I have found that this shape is better adapted to thepurpose for which it is used, and to be hereinafter described.

Numeral I2 represents an electrically conductive terminal end member or unit. After stamping, before it has been bent and shaped to adapt said member I2 for the purpose and function it is to perform and to be hereinafter described, said member preferably is of a form illustrated in Fig. 3. In its initial form, the end member I2 is preferably at and preferably includes an upper ovate-like body portion I3 with a rounded upper edge. The rounded edge of the ovate-like body portion I3 preferably merges into two parallel integral edges I6, Which edges I6 in turn merge into oppositely extending shoulders I4. An integrally formed shank or portion or holding member I extends inward from the body portion I3. A hole or space I'I is preferably formed at the geometric center of the body portion I3.

The procedure I employ in the preparation of the end member I2 for use is to cut the ovate body portion I3 substantially along its longitudinal axis down to the hole I'I, and bend the portion thus cut substantially 90 from the longitudinal axis so that substantially one half lof th-e hole I'I is at a right angle to the other half thereof. I also bend the member I2 along its entire central longitudinal axis so that an angle sufficiently small is formed at the inner end of the shank I5 to facilitate ease of insertion of said shank into said core; and one of which is sufficiently large at the outermost end of said shank, where said shank merges with the shoulders I4 to cause each of said members I2 to be frictionally retained in the respective ends of the core I0 when said members I2 are inserted in the holes II respectively so that the shoulders I4 are in abutment with the annular end faces of the cores I0 respectively. It is to be understood that the inherent nature of the metal causes the bent shank I5 to produce a spring-like tension which l aids in retaining end members I2 in their respective core openings. In its employed form, each member I2 has preferably two integral extensions or outer portions or members I8 which are parts of the body I3 which have been bent the above stated S0".

After the core Iii and end member I2 assembly is completed, so that one end member is positioned in each of holes il, said assemblies are normally moved through a wire Winding device in an endto-end relation.

For the purpose of illustrating the manner in which the end members I2 cooperate to insure an exact length of and uniformly spaced resistance wire being wound on the core i'l, I shalll show one method of winding to which the above described assemblies are adapted for Winding.

It is to be understood that the herein described positioning of the alar portions I8 precludes the overlapping and consequent tying together of terminal end members of adjacent cores by convolutions of resistance wire during a winding process, such as the one to be hereinafter described. Further, it is to be understood that after bending and shaping of the end member I2, the normally parallel sides or edges I6 of the ovate body portions I3 at the inner ends thereof are substantially coincident with the circumference of the annular faces of the cores IU respectively. Also, each of the edges 4S of the shank I5 at its point of juncture with the respective shoulders I4 securely seats and is positioned in one of the corners 4I, which is formed by the leg I9 to frctionally retain said end members, as illustrated in Fig. 5.

While the winding and mounting of the resistance wire 21 upon and about the core may be done either manually or with the aid of a rotatable gripping element which grips the core body, or in a variety of other manners, the assemblies of the core II! and the end members `I2 may be placed in a metal cylinder or sleeve 20, as illustrated in Fig. 1. A wheel 2ll is journaled on the end portion of this sleeve 20 by means of a suitable bearing 22, said bearing being secured in the passaged hub portion of the wheel 2| by means of a lock nut 23. A yieldable bushing 24 is mounted on the end of sleeve 2U, the same having a. passage of a size to permit pressing therethrough of core bodies to be Wound with resistance wire,

to prevent their rotation during the Winding'of the resistance wire thereon.

Numeral 25 designates a metal tube or cylinder which is disposed co-,axially with respect to the 5 sleeve 20 and positioned a short distance therefrom, said distance being less than the length of the core I0 and end member I2 assembly. A spool 26 containing resistance wire 2 is journaled on the sleeve 25 by means of retaining bushings or nuts 28. The end of the tube 25 nearest the cylinder 20 has mounted ther-ecn 4a yieldable and removable inwardly flanged bushing 29, Whose annular flange is adapted to frictionally engage the resistor cores as the same are moved and pressed therethrough.

The cylinder 22 is of sumcient length so that a number of core assemblies may be tted and moved therein in an end-to-end relation. The wheel 2I carries a projecting passage arm 30 which has an eyelet in the end thereof and through which the resistance wire is threaded so that the wire may be extended to the area between the bushings 24 and 2B, as indicated in Fig. 1.

The train of cores which are placed in end-toend relation in the cylinder 29 is moved at a substantially uniform rate oi speed to cause the resistor wire to be wound in a desired spaced apart relation on the core. During the Winding the frictional engagement of the annular flanges of the bushings 24 and 28 will prevent rotation of the core assemblies being moved therethrough. As the rear terminal end member I2 of .each core passes through the `path and position in which the wire is Wound, the Wire will continue vto be Wound around the end member so that `several spaced apart convolutions ofthe Wire Will be Wound thereupon.

When the resistance wire is wound around `the terminal end member I2, as stated, the frictional engagement of the bushing 28 will prevent rotation of the core, and as the wire continues tcbe wound without interruption of the rotation and of the progression of the train of cores, the wire will continue to be first wound about the 'termithoughalso frictionally engaging such c ore bodies next succeeding core, and continue being wound around the main core body; this while said succeeding core is held against rotation by the fric- Vtional engagement of the bushing 24. This cycle of winding continues as the train of cores is pushed through the cylinder and through said bushings and through the tube 25. The train of cores emerging from the outlet tube will be connected together by a segment of spirally Wound wire which extends from the alar portions I8 of the end members I'2 to the adjacent alar portions of the end member I2 of the adjacent core. This segment is cut, after emergence from the tube 25, to separate the individual core assemblies with the wire wound thereon.

Previously designed terminal members or their equivalents have not been adapted to this or similar methods of winding because there has been no meansY for keeping the successive convolutions of resistance wire being wound upon the portions corresponding to my end member I2 of adequate diameter. Consequently as the arm'3il would rotate and apply the resistance 21 to the terminal members, the diameter of the convolutions applied to the end members, or parts which correspond to my end member I2, was smaller than the diameter of the core. As the core I0 would come into position for application of the Wire to the surface thereon, the Wire being wound upon the terminal member was not able to immediately adapt to the change in size between the diameter of the end member and that of the core. Consequently, a number of convolutions of wire which were intended to be placed upon the surface of the core did not get'there. Also some of those convolutions which by chance happen to be applied to the end of the core would slip therefrom because the diameter of the core was greater than the diameter of the convolutions. Employing a terminal end member', such as the one which I have invented, precludes the occurrence of the above described objectionable phenomenon. By using my end member, we are able to wind resistance Wire 21 uniformly from the rear end member I2 of Vone core to the front end member I2 of the adjacent core to the adjacent core body I0, and so on, so that the wire disposes itself in uniformly spaced apart convolutions upon the core body I0 over the entire length thereof, the resistance wire 21 upon the said core Il'always being of substantially the same length on all the cores which are wound in any given method to which my core `I0 and end member i2 is adaptable.

Referring to Figs. 2, 6 and 7, numeral 3| represents an end cap which preferably has an integral upwardly and inwardly extending annular flange 32. A terminal circuit wire 33 projects through the space formed by the iiange 32 and an end portion 3d of said wire 33 is bent over the flange 3| and outwardly.

Preferably a non-conductive covering 33, of any suitable material, is applied to eachof'the cores IIJ and the resistance wire wound thereon, after the cores-are separated one from the other by severing the segments of resistance wire connecting the end members I2 thereof. An electrically' conductive end cap 3| is securely mounted on each of the ends ofthe core and end member assemblies after the application ofthe non-conductive coat 35. Because of the hole I1 each terminal member I2 is adapted to seat down beneath the inner end of the flange 32 of the end cap `3 I said end flange extending up through 6 the hole I1. The alar members I8 and the end portion 34 of the connecting circuit wire 33 are preferably secured within the end cap 3| by a fusible metal 39, such as solder.` Because a pellet .of fusible metal is used in securing the above said parts, which is of predetermined size, in the assembly of the completed resistor unit none of the fusible metal will spill out through the passage defined by the flange 3 I.

The core I0 does not come in contact with the metal of the cap 3|. The diameter between the annular wall 36 of the end cap 3| is substantially the same as the diameter of the core I0 with the non-conductive coat 35 thereon,'4 so that each cap will abut against or slightly overlap its respective end of said core. One of: said end caps 3| and circuit wire arrangements 33 is secured with respect to each end of the core II) and the end members I2 mounted thereon."

In one modied form of my invention the end cap 3| is formed with an integral outwardly extending flange 31. This form will permit the optional use of a solid sleeve or cylinder 38 of glass or some'other non-conductive solid to be placed over and around the core IIJ with the re'- sistance wire wound thereon. Optio-nally this modified form may be covered with a suitable nonconductive covering or coating 35. In the event the covering 35 is not used the height of the cap 3| must be such as to preclude the cap 3| from coming in contact with the resistance Wire wound upon the core I0.

In theevent, a sleeve 38 is not used, it is preferable to coat the entire hereinr described resistor unit, including the end caps 3|, l'with a second non-conductive material. An example of the material used for said non-conductive coating is one such as porcelain enamel which, when dried and baked, effectively-protects the resistor overits entire length. Such enamel coating has high heat conductivity and quickly dissipates the heat developed inthe resistor element.

The present invention has been described herein more or less as to details, yet is to be understood that the invention is not limited thereby, as changes may be made in the arrangement and proportion of parts, and equivalents may be substituted without departing from the spirit and scope of the invention.

I claim:

v l. In a resistor for electrical circuits and the like, a non-conductive core having an opening in each end thereof; an insertable metal terminal end member mounted on each end of said core, each of said terminal end members comprising a shank and a body portion integral `therewith, the outer ends of said body portions extending radially substantially to the projection of the curved plane of said core, and said body portion having an integral portion of said body portion bent substantially perpendicularly thereto, said body portion and said shank being bent along the longitudinal axis'thereof so that a tapered angle is formed along said axis of said shank, the innermost portion 'of said shank normally being in non-abutment with said core, the remainder of said shank normally frictionally abutting in each of said core openings; each of said body portions having a hole 'therein at the center thereof; a resistance wire spirally wound around said core and each'of'saidend members;

a metal end cap electricallyy connected to and 'formed inwardly extending iiange, said flange enamore .passing through 'sani hole in `said terminal end member, :anda connecting Vcircuit wire secured to .each of said end caps.

l2. In .combination with a resistor Afor electrical .circuits andthe like, a core having an opening in each end thereof; an electrically conductive and `slida'bly insertable terminal end member l.mounted on eac-h end of said core, each of said terminal end members comprising a spring-like tapered shank .and an integral body portion, said shank being .retained in said core openings by the engagement of portions thereof with .said Vvcorefthe inner portions of the sidev edges vof said shank zbeing in non-engagement with said core; and .a resistance Wire spirally wound around said -core and said end members.

3. In a resistor for electrical -circuits and the zlike. .an open ended nonconductive core, said openings being multiangular; a metal terminal end member Amounted on each end of .said core, said terminal 'end -members bhaving a sha-nk in- 4tegral with the body thereof, the outer ends of 'each of said bodies extending outwardly substantially to the .general curved plane -of said core, and said body having an 'integral portion thereof -bent substantially perpendicularly thereto, vsaid body and said shank being bent along the longitudinal axis thereof and being gradually tapered inwardly; said outer portions-of the lat- 4eral edgesof 4said sha-nk normally abutting two of lthecorners of said core opening, said end members normally being retained in `said openings by engagement of said lateral edge portions; a 're- -sistance wire Wound spirallyaroundsaid .core and each of saidendxmembers; -a lmetal end cap -conductively connected to and enveloping each of said terminal end members; and a connecting circuit wire secured to each of said end caps.

\- 4. In a .resistor for electrical circuits and the like, a non-conductive vcore having'end openings, 4said openings in said core being .multilateral; a metal terminal end .member mounted on each end orsaid core, each of said terminal end menibers having an integral reduced Shank, the op .posite end edges of said members being substarri Itially coincident with the peripheral projection of the end faces of said core, and said end members .having an integral portion of each thereof bent substantially perpendicularly thereto, said end members being bent along substantially a longitudinal .axis thereof, thev inner portion of .the .angle of said shank being smaller .than vthe angle of the remainder of said end memberthereof, the edges of said shank normally 4abutting in and frictionally engaging in o-ne of said core openings, each of said end members .having a central hole therein; a Wire wound in spiral con- Avolutions around said core, said convoiutions being of predetermined resistance and uniformly distributed over the length of sai-d core; a nonconductive coating covering said core and said resistance wire Wound thereon; a metal end cap electrically connected to and `enveloping each of said inwardly projecting ange `of saidl cap. i

5. In combination with a resistor for electrical feiruife and. ihelikee:ecilwonduetire; Cere .pre-

vid'ing an opening at each end thereof; .a metal terminal end member mounted on each end of said core, each of said terminal end members iincluding a shank integral with a body, the lateral edges of said bodies being substantially co- .incident with the periphery of the end faces of said core, said body having an integral portion of said body bent substantially perpendicularly thereto, said body and said shank being bent alo-ng the longitudinal axis thereof to form a tapered angle, .the inner portion of said angle of rsaid shank being smaller than the langle lformed at the top thereof to facilitate insertion of said end member into said core; each of said shanks at the outer portion thereof normally .frictionally abutting in one of said openings respectively, each of said end members .having a. Vcentral hole therein; a resistance Wire 0f predetermined resistance wound in `spiral convolutions around said core, said convolutions being uniformly .distributed over the lengthof said core; Va metal end cap electrically connected to and enveloping v,each of said terminal end members, saidend cap having an inwardly projecting extension, said extension passing through the hole in the adjacent terminal end member, said end caps each having an annular peripheral flange;

a connecting terminal circuit Wire securely lmounted in each of said end caps, each of .said

circuitwires having a bent end portion; each of .said bent portions extending around said inward- A1y projecting iiange; a ,fusible metal connecting veach of said endcaps with the adjacent .termi- .nal end member and with the bent end portion respectively, said fusible metal being of apredetermined amount so thatin the fusing thereof .none will spill from the cap; and a non-.con-

defining said openings, the side edges and inner- .most part of Said reduced portion being in nonengagement with said core; a resistance wire 4wound spirally around said core and each ofsai end members.

7. In a resistor for electrical circuits .and the like, a non-conductive core having end openings, said openings in said core being multilateral; `a

`metal terminal end member mounted on each end of said core, each of sai-:l terminal end members having an integral reduced shank, the edges of the ends of said members extending substantially lto the largest `dimension of the peripheral projection of the adjacent end faces of said core and -sai'd' end members each .having an .integral "portion thereof bent substantially perpendiculariy thereto, said Y,end members being bent along vthe longitudinal axis. thereof, the inner portion .of -the angle of said shank being smaller than portions .of the angle of the remainder of v`said .end

member thereof to facilitate easy insertion of said end members in said core opening respectively, the edges of said shank normally abuttingin -and frictionally engaging in one of said core .'Openings. each lof said end members .having 'a central hole therein; a wire wound in spiral convolutions around said core, said convolutions be ing of predetermined resistance and uniformly distributed over the length of said core; a metal end cap electrically connected to and enveloping each of said terminal end members, said end cap having an integrally formed inwardly extending flange defining an opening, said flange passing through the hole in the adjacent terminal end member, and a connecting terminal circuit wire securely mounted in each of said end caps, each of said circuit wires having a bent end portion, said circuit Wire passing through the opening in said end cap, said bent portion extending around said inwardly projecting flange of said cap.

8. In combination with a resistor for electrical circuits and the like, an open ended non-conductive core; a slidably insertable electrically conductive terminal end member mounted on each end of said core, each of said terminal end members having a spring-like shank integral with a body, the end edges of said bodies being substantially coincident with portions of the peripheral projections of the adjacent end faces of said core,

and said body having an integral portion thereof bent substantially perpendicularly thereto, said shank at outer portions thereof normally en-` openings being multiangular; a metal terminal end member mounted on each end of said core, said terminal end members having a shank integral with the body thereof, the outer ends of each of said bodies extending outwardly substantially to the general curved plane of said core, and said body having an integral portion thereof bent substantially perpendicularly thereto, said body and said shank being bent along the longitudinal axis thereof and being gradually tapered inwardly; said outer portions of the lateral edges of said shank normally abutting two of the corners of said core opening, said end members normally being retained in said openings by engagement of said lateral edge portions; and a resistance wire wound spirally around said core and each of said end members.

JOSEPH J. CERNY.

REFERENSES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS France Jan. 30, 1939 

